Washington County, Missouri Natural Disaster Risk
FEMA National Risk Index assessment · MO
LowComposite Risk Score
National percentile: 68th
Washington County faces low composite natural disaster risk (NRI Risk Index score 67.8, 68th national percentile), driven primarily by heat wave and cold wave exposure. Expected annual loss across all 18 hazard types is $20M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Risk Overview
FEMA's National Risk Index rates Washington County at low composite risk, with a National Risk Index score of 67.8 out of 100 — placing it in the 68th national percentile and below the national average for natural-disaster risk. The score blends Expected Annual Loss, Social Vulnerability, and Community Resilience across all 18 FEMA hazard types.
Risk here concentrates in heat wave (prolonged periods of extreme heat that threaten health and infrastructure) at Medium risk — $6M in expected annual loss and about 10.89 events per year; cold wave (prolonged spells of dangerously low temperatures) at Medium risk — $4M in expected annual loss and about 1.37 events per year; and earthquake (ground shaking from sudden movement along geologic faults) at Low risk — $2M in expected annual loss and about 0.01 events per year. Across all hazards, FEMA estimates $20M in expected annual loss for a population of 23K.
Beyond physical exposure, Washington County has a high social vulnerability rating (how susceptible the population is to harm) and a very low community resilience rating (its capacity to prepare for and recover from disasters). That combination — a more vulnerable population with limited resilience — can amplify the human cost of any given event.
History supports the rating: Washington County has received 27 federal disaster declarations since 1973, including 16 for severe storm events and 5 for flood events. The most recent was Severe Storms, Straight-Line Winds, Tornadoes, and Flooding (severe storm), declared in June 2025.
Among 115 Missouri counties, Washington County ranks #31 for overall natural disaster risk.
Top Hazards
All 18 Hazard Risks
| Heat Wave | Medium | 10.89 / yr | $6M |
| Cold Wave | Medium | 1.37 / yr | $4M |
| Earthquake | Low | 0.01 / yr | $2M |
| Landslide | Low | 2.31 / yr | $11K |
| Strong Wind | Medium | 4.52 / yr | $831K |
| Tornado | Medium | 0.48 / yr | $2M |
| Ice Storm | Low | 0.93 / yr | $93K |
| Wildfire | Very Low | 0.00 / yr | $50K |
| Riverine Flood | Low | 0.86 / yr | $5M |
| Hail | Low | 4.69 / yr | $215K |
| Lightning | Low | 53.92 / yr | $140K |
| Winter Weather | Low | 8.68 / yr | $39K |
| Hurricane | Very Low | 0.02 / yr | $11K |
| Drought | Very Low | 2.54 / yr | $4K |
| Avalanche | Very Low | 0.00 / yr | $0 |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Disaster History
Washington County has received 27 federal disaster declarations since 1973, most recently Severe Storms, Straight-Line Winds, Tornadoes, and Flooding in June 2025. Most frequent causes: Severe Storm (16), Flood (5), Biological (2).
| Declared | Type | Disaster |
|---|---|---|
| June 2025 | Severe Storm | Severe Storms, Straight-Line Winds, Tornadoes, and Flooding |
| May 2025 | Severe Storm | Severe Storms, Straight-Line Winds, Tornadoes, and Flooding |
| January 2025 | Severe Storm | Severe Storms, Tornadoes, Straight-Line Winds, and Flooding |
| March 2020 | Biological | Covid-19 Pandemic |
| March 2020 | Biological | Covid-19 |
| June 2017 | Flood | Severe Storms, Tornadoes, Straight-Line Winds and Flooding |
| January 2016 | Flood | Severe Storms, Tornadoes, Straight-Line Winds, and Flooding |
| January 2016 | Flood | Severe Storms, Tornadoes, Straight-Line Winds, and Flooding |
| August 2015 | Severe Storm | Severe Storms, Tornadoes, Straight-Line Winds, and Flooding |
| May 2011 | Severe Storm | Severe Storms, Tornadoes, and Flooding |
Showing the 10 most recent of 27 declarations.
Source: FEMA Disaster Declarations Summaries (OpenFEMA).
Frequently Asked Questions
What is the overall natural disaster risk for Washington County?
Washington County has a composite FEMA National Risk Index score of 67.8 out of 100, placing it in the Low category and the 68th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Washington County?
The three highest-rated hazards are Heat Wave (Medium, $6M EAL), Cold Wave (Medium, $4M EAL), Earthquake (Low, $2M EAL). These account for most of the county's expected annual losses.
How does Washington County compare to other Missouri counties?
Washington County ranks #31 of 115 Missouri counties for overall natural disaster risk, with a low rating.
How many federally declared disasters has Washington County had?
FEMA records 27 federal disaster declarations for Washington County since 1973, most often 16 for severe storm events and 5 for flood events. The most recent was Severe Storms, Straight-Line Winds, Tornadoes, and Flooding, declared in June 2025.
What does Expected Annual Loss (EAL) mean?
EAL is FEMA's estimate of average annual dollar losses from natural hazards, calculated from historical event data and exposure models. Washington County's $20M EAL is a statistical average, not a guarantee for any specific year or address.